Removing text before "iomark" can be done by using the underlying Text widget directly. See how the Squeezer extension does this in issue1529353. This should simplify the implementation significantly.


I also took a look at the version of the extension in IdleX. I'm thinking of adapting this for CPython's IDLE. Some questions:

1. Is there a reason that text.dump() isn't called inside ClearWindowDeleteCommand.do()?
2. What is the purpose of strip_ansi()?
3. Does IDLE support multi-line prompts, or is that just IdleX? As a side note, it seems that in IDLE the debugger will override the prompt with '>>> ' whenever it is shut down (see PyShell.close_debugger); perhaps this is a bug?
4. I see ClearWindowDeleteCommand just calls text.delete() and text.insert to modify text before the iomark. Will this work on regular IDLE as well, or this is possible only in IdleX?